Monitoring of glucocorticoid therapy by assessment of CD14(+)CD16(+) monocytes: a case report

Systematic Review of Systemic Corticosteroids for Treatment of Organizing Pneumonia

Introduction

Regardless corticosteroids are recommended for the treatment of organizing pneumonia there is limited evidence supporting this practice. Thus, we performed a systematic review of the literature on systemic corticosteroid treatment for organizing pneumonia.

Methods

A search was implemented in the PubMed database (Medline) for articles published in the last 20 years. Those studies with incomplete or insufficient data and case reports were excluded. We collected data including: demographics, clinical data, diagnostic procedures, aetiology, treatment regimen (drug, posology, duration, response) and evolution.

Results

A total of 135 publications were selected and finally 13 studies with 849 patients were included in the review: 12 retrospective observational studies and a single prospective observational study. Most of the patients were started on treatment with systemic corticosteroids - a total of 627 (30-100% depending on the series), but there was a great heterogeneity regarding drug, doses and duration. On those that started treatment, 226 (36%) presented a relapse of the disease during follow-up. Only one study provided information regarding treatment side-effects.

Conclusion

The findings of this systematic review show the low quality data supporting the use of corticosteroids for the treatment of organizing pneumonia. This highlights a need to undertake appropriately designed studies to investigate which is the most appropriate treatment regimen that trades off benefits and risks of prolonged corticosteroid administration.

CD14++ CD16- monocytes are the main source of 11β-HSD type 1 after IL-4 stimulation

The anti-inflammatory actions of IL-4 are well established through earlier findings. However, the exact mechanism it uses to downregulate the pro-inflammatory cytokine production through monocytes and macrophages is poorly understood. In this study, we examined the effect of IL-4 in the induction of 11β-HSD1 in the two main classes of monocytes, CD14⁺⁺ CD16^- (CD14) and CD14⁺ CD16⁺ (CD16). Peripheral Blood Mononuclear Cells (PBMCs) were isolated from 17 healthy donors and were sorted into CD14 and CD16 subpopulations using cell sorting. Effect of IL-4 on 11β-HSD1-enzyme activity was measured in sorted and unsorted monocytes using Homogeneous Time-Resolved Fluorescence (HTRF) and M1/M2 polarization analysis was performed by flow cytometry. Our results indicate that CD14 cells are the major source of 11β-HSD1 enzyme after IL-4 stimulation and that M2 phenotype is not a pre-requisite for its synthesis.

Human monocyte subsets exhibit divergent angiotensin I-converting activity

Immune cells may take part in the renin-angiotensin-aldosterone system (RAAS), which plays a pivotal role in the regulation of vascular tone and blood pressure. The aim of the study was to analyse the expression and activity of angiotensin-converting enzyme type 1 (ACE1) and ACE2 in human monocytes (MO) and their subsets. The highest relative level of ACE1-, as well as ACE2-mRNA expression, was observed in CD14(++)CD16(-) (classical) MO. Moreover, in these cells, mean level of ACE2-mRNA was almost two times higher than that of ACE1-mRNA (11.48 versus 7.073 relative units, respectively). In peripheral blood mononuclear cells (PBMC), MO and classical MO, ACE1 and ACE2 protein expression was stronger compared to other MO subpopulations. The highest level of Ang II generated from Ang I in vitro was observed in classical MO. In this setting, generation of Ang-(1-9) by PBMC and classical MO was higher when compared to the whole MO population (P < 0.05). The generation rate of vasoprotective Ang-(1-7) was comparable in all analysed cell populations. However, in CD14(+)CD16(++) (non-classical) MO, formation of Ang-(1-7) was significantly greater than Ang II (P < 0.001). We suggest that in physiological conditions MO (but also lymphocytes forming the rest of PBMC pool) may be involved in the regulation of vessel wall homeostasis via the RAAS-related mechanisms. Moreover, non-classical MO, which are associated preferentially with the vascular endothelium, express the vasoprotective phenotype.

Standardized single-platform assay for human monocyte subpopulations: Lower CD14+CD16++ monocytes in females

We present a novel single-platform assay for determination of the absolute number of human blood monocyte subpopulations, i.e., the CD14(++)CD16(-) and the CD14(+)CD16(++) monocytes. A four-color combination of antibodies to CD14, CD16, CD45, and HLA-DR reduces the spill-over of natural killer cells and of granulocytes into the CD14(+)CD16(++) monocyte gate. For these CD14(+)CD16(++) monocytes, the intra-assay coefficient of variation (CV) was 4.1% and the inter-assay CV was 8.5%. Looking at a cohort of 40 donors aged 18-60 years, we found no age dependence. There was however an effect of gender in that females had lower CD14(+)CD16(++) monocytes (45.4 +/- 13.5 cells/microl) compared with males (59.1 +/- 20.3 cells/microl) (P < 0.02). Using this novel approach, we can confirm that exercise will lead to more than three-fold increase of the CD14(+)CD16(++) monocytes. Also, we show that therapy with low doses of glucocorticoids will deplete these cells. This robust single-platform assay may be a useful tool for monitoring the absolute number of monocyte subpopulations in health and disease.

Characterization of monocyte/macrophage subsets in the skin and peripheral blood derived from patients with systemic sclerosis

Introduction

Recent accumulating evidence indicates a crucial involvement of macrophage lineage in the pathogenesis of systemic sclerosis (SSc). To analyze the assembly of the monocyte/macrophage population, we evaluated the expression of CD163 and CD204 and various activated macrophage markers, in the inflammatory cells of the skin and in the peripheral blood mononuclear cells (PBMCs) derived from patients with SSc.

Methods

Skin biopsy specimens from 6 healthy controls and 10 SSc patients (7 limited cutaneous SSc and 3 diffuse cutaneous SSc) were analyzed by immunohistochemistry using monoclonal antibody against CD68 (pan-macrophage marker), CD163 and CD204. Surface and/or intracellular protein expression of CD14 (marker for monocyte lineage), CD163 and CD204 was analysed by flow cytometry in PBMCs from 16 healthy controls and 41 SSc patients (26 limited cutaneous SSc and 15 diffuse cutaneous SSc). Statistical analysis was carried out using Mann-Whitney U test for comparison of means.

Results

In the skin from SSc patients, the number of CD163⁺ cells or CD204⁺ cells between the collagen fibers was significantly larger than that in healthy controls. Flow cytometry showed that the population of CD14⁺ cells was significantly greater in PBMCs from SSc patients than that in healthy controls. Further analysis of CD14⁺ cells in SSc patients revealed higher expression of CD163 and the presence of two unique peaks in the CD204 histogram. Additionally, we found that the CD163⁺ cells belong to CD14^brightCD204⁺ population.

Conclusions

This is the first report indicating CD163⁺ or CD204⁺ activated macrophages may be one of the potential fibrogenic regulators in the SSc skin. Furthermore, this study suggests a portion of PBMCs in SSc patients abnormally differentiates into CD14^brightCD163⁺CD204⁺ subset. The subset specific to SSc may play an important role in the pathogenesis of this disease, as the source of CD163⁺ or CD204⁺ macrophages in the skin.